For example, devices of the type in question are, although not exclusively, utilized in so-called hot runner moulds, in which the moulding mass to be processed is injected into the mould cavity in a timed fashion via heated channels, valves and nozzles. In this case, the injection nozzles are typically realized in the form of needle valves or needle-type nozzles, in which the point of a needle is pressed against a seat in the nozzle member which is realized complementary with respect to the shape and function of the needle in order to close the nozzle and lifted off said seat in order to open the nozzle.
In one known device, the needle is stationarily arranged on a piston plate that is supported in a receptacle such that it can be displaced in both axial directions similar to a double-action cylinder, wherein a first work chamber is formed on the side of the piston plate which faces away from the needle and a second work chamber is formed on the opposite side of the piston plate, wherein the second work chamber can be acted upon with a fluid in order to actuate the needle, and wherein the needle extends outward from the second work chamber through a recess in an end element that lies opposite of the piston plate. One disadvantage of this known device can be seen in the fact that the piston plate has a comparatively large mass. If several needles are provided, the constructive design also results in a comparatively large spacing between the needles or injection nozzles.
Based on this state of the art, the invention aims to develop a device of the previously described type which has smaller moving masses and makes it possible to achieve a small spacing between adjacent needles and consequently several injection nozzles per surface unit.